Sodium metasilicate is a silicic acid salt, classified as an inorganic salt product. It is non-toxic, harmless, and odorless, with purifying, emulsifying, moistening, dispersing, permeating, and PH buffering abilities. As an aqueous solution, it is capable of hygroscopy and deliquescence when in contact with air. Its forms include anhydrous, pentahydrate, and nonahydrate compounds.

It is estimated to be generally less aggressive and safer to use than caustic soda (sodium hydroxide). Sodium silicate reacts with metal oxides to establish a protective film on metal surfaces, reducing the alkali’s tendency to corrode and dissolve metals. This sort of protection is maintained as long as minute amounts of soluble silica remain in the presence of water.